Prosecution Insights
Last updated: April 19, 2026
Application No. 17/437,194

PROCESS FOR PRODUCING POLYCARBONATE - POINT OF ADDITION OF THE CHAIN TERMINATOR

Final Rejection §103§DP
Filed
Sep 08, 2021
Examiner
NGUYEN, HA S
Art Unit
1766
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Covestro Intellectual Property GmbH & Co. Kg
OA Round
4 (Final)
57%
Grant Probability
Moderate
5-6
OA Rounds
3y 4m
To Grant
36%
With Interview

Examiner Intelligence

Grants 57% of resolved cases
57%
Career Allow Rate
341 granted / 599 resolved
-8.1% vs TC avg
Minimal -21% lift
Without
With
+-21.3%
Interview Lift
resolved cases with interview
Typical timeline
3y 4m
Avg Prosecution
47 currently pending
Career history
646
Total Applications
across all art units

Statute-Specific Performance

§101
1.1%
-38.9% vs TC avg
§103
39.2%
-0.8% vs TC avg
§102
25.4%
-14.6% vs TC avg
§112
20.2%
-19.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 599 resolved cases

Office Action

§103 §DP
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Response to Amendment The previous objection of Claim 20 under 37 CFR 1.75 as being a substantial duplicate of claim 7 is/are withdrawn in light of the Applicant’s amendments. The previous rejection of Claims 1, 2, 5-18, and 20, provisionally on the ground of nonstatutory double patenting as being unpatentable over claims 1-20 of copending Application No. 17/439,889 (App. No. 17/439,889) is/are withdrawn in light of the Applicant’s amendments. The previous rejection of Claim(s) 1, 2, 5-20, under 35 U.S.C. 102(a)(1) as being anticipated by US 2005/0020804 A1 to Rohde et al. (hereinafter Rohde) is/are withdrawn in light of the Applicant’s amendments. The previous rejection of Claim(s) 1, 2, 5-20, under 35 U.S.C. 102(a)(1) as being anticipated by US 2011/0224372 A1 to Jueptner et al. (hereinafter Jueptner) is/are withdrawn in light of the Applicant’s amendments. The previous rejection of Claim(s) 1, 2, 5-20, under 35 U.S.C. 102(a)(1) as being anticipated by US 6,225,436 B1 to Eiffler et al. (hereinafter Eiffler) as evidenced by Rohde and/or Jueptner is/are withdrawn in light of the Applicant’s amendments. Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. Claim(s) 1, 2, 5-19, 21, and 22, is/are rejected under 35 U.S.C. 103 as being unpatentable over US 2005/0020804 A1 to Rohde et al. (hereinafter Rohde). Regarding claims 1, 2, 5-19, 21, and 22, Rohde teaches in Example 1, a process of producing branched polycarbonate by mixing in a reactor bisphenol A, and a caustic solution (30 wt% NaOH in water), adding trishydroxyphenolethane (THPE), dichloromethane, and starting phosgenation with a phosgene flow at 0.04 g/s (para 46-59). The phosgenation oligomerization reaction has the following intermediate PNG media_image1.png 222 386 media_image1.png Greyscale , where y is less than 10 (para 59-60), which meets the claimed reaction product R, and the y is less than 10 overlaps and meets the claimed degree of polymerization of 1 to 5 units. (See MPEP 2144.05, “where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists”). Rohde further teaches that after 55 minutes and 1/3 of the phosgene amount has been added, t-butyl phenol is fed to the reaction to control molecular weight, and after another 112 minutes of phosgene addition, a caustic addition (30 wt% NaOH in water) was added. (para 61). Triethylamine (TEA) catalyst is then added when the polymer molecular weight is about 1,200 to about 1,500 g/mol, (para 41 and 61), and after the rest of the phosgene is added and phosgenation has stopped, a late addition of TEA is added, and reacted for 15 minutes to stop the coupling reaction and the polycarbonate is recovered. (para 61). Rohde also teaches the phosgene is used in an amount of 1.2 to 1.5 mols per mol of bisphenol A (para 23), and the interfacial polymerization has about 2 to 4 moles of aqueous alkali metal hydroxide solution per mole of dihydric phenol compound. (para 31). The above reaction can also be a continuous process. (para 30). Rohde further teaches that the above process provides a more improved production of improved branched polycarbonates with improved melt viscosity and shear viscosity. (para 13 and 42). The above reaction mixture meets the claimed reaction system with bisphenol A, phosgene, and the reaction product R. The above p-t-butyl phenol meets the chain terminator added before the first addition of the NaOH solution, and the continued addition of phosgene meets the “unreacted” phosgene in the reaction system. The above 1.2 to 1.5 mols of phosgene per 1 mol of bisphenol A also correlates to 9.1 to 20 mol% excess phosgene relative to bisphenol A and meets claim 7. The above intermediate polymer having the formula PNG media_image1.png 222 386 media_image1.png Greyscale , where y is less than 10 (para 59-60), which meets the claimed reaction product R, and the y is less than 10 overlaps and meets the claimed degree of polymerization of 1 to 5 units. (See MPEP 2144.05, “where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists”). It would have been obvious to one ordinarily skilled in the art before the effective date of the claimed invention for the intermediate polymer of Rohde to have the claimed degree of polymerization of one to five units because Rohde teaches the above intermediate polymer having the formula PNG media_image1.png 222 386 media_image1.png Greyscale , where y is less than 10 (para 59-60), which overlaps and meets the claimed degree of polymerization of 1 to 5 units. (See MPEP 2144.05, “where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists”), and Rohde further teaches that the above process provides a more improved production of improved branched polycarbonates with improved melt viscosity and shear viscosity. (para 13 and 42). Claim(s) 1, 2, 5-19, and 21-23, is/are rejected under 35 U.S.C. 103 as being unpatentable over US 2011/0224372 A1 to Jueptner et al. (hereinafter Jueptner). Regarding claims 1, 2, 5-19, and 21-23, Jueptner teaches in Example 1, a process of producing branched polycarbonate by mixing in a reactor bisphenol A, and a caustic solution (30 wt% NaOH in water), adding dichloromethane, and starting phosgenation with a phosgene flow at 0.06 g/s (para 45-57). The phosgenation oligomerization reaction has the following intermediate PNG media_image1.png 222 386 media_image1.png Greyscale , where y is less than 10 (para 57), which meets the claimed reaction product R and overlaps and meets the claimed degree of polymerization of 1 to 5 units. (See MPEP 2144.05, “where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists”). Jueptner further teaches that after 37.5 minutes and 1/3 of the phosgene amount has been added, t-butyl phenol is fed to the reaction to control molecular weight, and after another 75 minutes of phosgene addition , a caustic addition (30 wt% NaOH in water) was added. (para 58). Triethylamine (TEA) catalyst is then added when the polymer molecular weight is 1,500 g/mol, (para 58), and after the rest of the phosgene is added and phosgenation has stopped, a second addition of TEA is added, and reacted for 15 minutes to stop the coupling reaction and the polycarbonate is recovered. (para 58). Jueptner also teaches the phosgene is used in an amount of 1.2 to 1.5 mols per mol of bisphenol A (para 27), and the interfacial polymerization has about 2 to 4 moles of aqueous alkali metal hydroxide solution per mole of dihydric phenol compound. (para 33). The above reaction can also be a continuous process. (para 31). Jueptner also teaches that the above process provides for an improved production of linear polycarbonates with reduced level of oligomers and better impact strength, and ductile brittle transition temperature performance. (para 8-9, 21, and 44). The above reaction mixture meets the claimed reaction system with bisphenol A, phosgene, and the reaction product R. The above p-t-butyl phenol meets the chain terminator added before the first addition of the NaOH solution, and the continued addition of phosgene meets the “unreacted” phosgene in the reaction system. The above intermediate polymer wherein y is less than 10 (para 57), meets the claimed reaction product R and overlaps and meets the claimed degree of polymerization of 1 to 5 units. (See MPEP 2144.05, “where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists”). The above 1.2 to 1.5 mols of phosgene per 1 mol of bisphenol A also correlates to 9.1 to 20 mol% excess phosgene relative to bisphenol A and meets claim 7. It would have been obvious to one ordinarily skilled in the art before the effective date of the claimed invention for the intermediate polymer of Jueptner to have the claimed degree of polymerization of one to five units because Jueptner teaches the above intermediate PNG media_image1.png 222 386 media_image1.png Greyscale , where y is less than 10 (para 57), which meets the claimed reaction product R and overlaps and meets the claimed degree of polymerization of 1 to 5 units, (See MPEP 2144.05, “where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists”), and Jueptner also teaches that the above process provides for an improved production of linear polycarbonates with reduced level of oligomers and better impact strength, and ductile brittle transition temperature performance. (para 8-9, 21, and 44). Response to Arguments Applicant's arguments filed 08/06/2025 have been fully considered but they are not persuasive. On page 8, the Applicant argues that the Rohde and Jueptner fail to teach the average degree of polymerization of one to five units. This is not persuasive because, as cited above, both Rohde and Jueptner teaches wherein the polymerization degree is less than 10, which meets the claimed reaction product R and overlaps and meets the claimed degree of polymerization of 1 to 5 units, (See MPEP 2144.05, “where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists”). On page 9, the Applicant argues that Jueptner states that y of 10 to 15 is preferred over smaller ones. This is not persuasive because Jueptner teaches a y of less than about 10 to 15,” (para 57) and further teaches that smaller polymerization units are preferred by their example having a Mw of 1,500 g/mol which is a polymerization degree of about 5.9, which is less than 10. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to HA S NGUYEN whose telephone number is (571)270-7395. The examiner can normally be reached Mon-Fri, Flex schedule 7:30am-3:45pm. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Randy Gulakowski can be reached at (571)272-1302. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /HA S NGUYEN/Primary Examiner, Art Unit 1766
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Prosecution Timeline

Sep 08, 2021
Application Filed
Jun 10, 2024
Non-Final Rejection — §103, §DP
Sep 11, 2024
Response Filed
Sep 11, 2024
Response after Non-Final Action
Sep 30, 2024
Response Filed
Nov 21, 2024
Final Rejection — §103, §DP
Jan 27, 2025
Examiner Interview Summary
Jan 27, 2025
Response after Non-Final Action
Jan 27, 2025
Applicant Interview (Telephonic)
Apr 16, 2025
Request for Continued Examination
Apr 16, 2025
Response after Non-Final Action
Apr 18, 2025
Response after Non-Final Action
May 02, 2025
Non-Final Rejection — §103, §DP
Aug 06, 2025
Response Filed
Oct 22, 2025
Final Rejection — §103, §DP (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

5-6
Expected OA Rounds
57%
Grant Probability
36%
With Interview (-21.3%)
3y 4m
Median Time to Grant
High
PTA Risk
Based on 599 resolved cases by this examiner. Grant probability derived from career allow rate.

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